Merge pull request #4399 from edx/feanil/update_metrics_script

Make it so we update alarms even when they already exist.

util/jenkins/check-celery-queues.py

@@ -143,11 +143,8 @@ def check_queues(host, port, environment, deploy, max_metrics, threshold,
         alarm_name = "{}-{} {} queue length over threshold".format(environment,
                                                                    deploy,
                                                                    queue)
-        if len(cloudwatch.describe_alarms_for_metric(Namespace=namespace,
-                                                     MetricName=metric_name,
-                                                     Dimensions=dimensions)
-                ['MetricAlarms']) < 1:
-            print('Creating new alarm "{}"'.format(alarm_name))
+        
+        print('Creating or updating alarm "{}"'.format(alarm_name))
         cloudwatch.put_metric_alarm(AlarmName=alarm_name,
                                     AlarmDescription=alarm_name,
                                     Namespace=namespace,